The McLafferty rearrangement is a reaction observed in mass spectrometry during the fragmentation or dissociation of organic molecules. It is sometimes found that a molecule containing a keto-group undergoes β-cleavage, with the gain of the γ-hydrogen atom, as first reported by Anthony Nicholson working in the Division of Chemical Physics at the CSIRO in Australia.[1] This rearrangement may take place by a radical or ionic mechanism.
A description of the reaction was later published by the American chemist Fred McLafferty in 1959 leading to his name being associated with the process.[2][3][4]
